dear mr. bach-man or to whoever else who can help me,

i have recently got my santa fe flyer train set, (maybe 1-2 years ago) and now the engine turns on and off around the track. whenever it passes by my nose when i inspect it, i can hear a faint crackling sound and a smell of battery. any idea what i should do? :-( it also sort of hesitates over the rail with the power wire input. it might be the track, too. i have seen some 'rust' or something on it, sort of grey-ish in appearance.

the rails, you can sort of see the grey area.

thanks if you can help!
by the way, hi everyone. :-)